Search Results (132)

Black soldier fly larvae meal has emerged as a sustainable alternative to fishmeal (FM) in aquafeeds. However, the use of full-fat black soldier fly larvae meal (FF-BSFL) may be limited by its relatively high lipid and chitin contents, which could affect nutrient digestibility and fish performance. This study determined the apparent digestibility coefficients (ADCs) of FF-BSFL and evaluated the effects of replacing 0%, 30%, 60%, and 100% of FM with FF-BSFL in diets for juvenile pacu (Piaractus brachypomus). A 60-day feeding trial was conducted using 320 juvenile pacu (initial weight: 3.0 g) to evaluate growth performance, serum biochemical parameters, and intestinal histomorphology. The results showed high ADCs for protein (88.76%), lipids (97.09%), and gross energy (85.96%) in FF-BSFL. Fish fed the diet containing 30% FM replacement exhibited growth performance comparable to the control group. However, replacement levels of 60% and 100% significantly reduced growth and feed efficiency. Furthermore, high fishmeal replacement levels decreased mucosal thickness and muscularis thickness, reduced goblet cell abundance, and increased serum triglyceride concentrations and aspartate aminotransferase (AST) activity. In conclusion, FF-BSFL was highly digestible for juvenile pacu. Replacement of up to 30% of FM maintained growth performance and intestinal integrity, whereas higher replacement levels negatively affected growth performance and intestinal health. Full article

Body color brightness is a key determinant of ornamental value in koi, yet nutritional strategies targeting structural coloration mediated by iridophores remain underexplored. Fish scale meal (FSM), an abundant fishery by-product, contains guanine and collagen, which may contribute to structural coloration and body brightness. This study evaluated the effects of partial replacement of fish meal with FSM on growth performance, body color parameters, pigment accumulation, iridophore density, and iridophore-related gene expression in koi. A total of 384 koi with an initial body weight of 19.02 ± 0.18 g were randomly assigned to six dietary treatments for 8 weeks, with FSM inclusion levels ranging from 0% to 9.55%, corresponding to 0–100% replacement of dietary fish meal. Growth performance, including final body weight, weight gain rate, and specific growth rate, decreased with increasing FSM inclusion. Body lightness (L*) and scale guanine content increased progressively with FSM level and reached their highest values at 9.55% FSM, whereas redness (a*), yellowness (b*), and total carotenoid content showed the opposite trend. Iridophore density was significantly higher in the 3.82–5.73% FSM groups than in the other treatments. The expression of iridophore-related genes, including sox10, pax3, ltk, alx4a, and foxd3, showed non-linear responses and generally reached higher levels at moderate FSM inclusion, whereas pka showed an opposite transcript pattern. Overall, dietary FSM inclusion elicited trait-dependent responses in koi. Low or no FSM inclusion was preferable for maintaining growth, intermediate inclusion was more favorable for iridophore development, whereas higher FSM inclusion enhanced brightness-related traits. These findings suggest that FSM should be used according to the intended production objective, with inclusion levels adjusted for growth maintenance, iridophore-related coloration improvement, or brightness enhancement. Full article

The goal of this study was to replace the costly fishmeal (FM) with Tenebrio molitor larvae meal (TMLM) in diets for Nile tilapia (Oreochromis niloticus) juveniles. Six isonitrogenous diets were created in order to examine the viability of substituting FM protein with stepwise inclusion levels of TMLM protein, i.e., 0%, 15%, 30%, 45%, 60%, and 75% represented by TMLM0, TMLM15, TMLM30, TMLM45, TMLM60, and TMLM75, respectively. For 90 days, Nile tilapia juvenile (8.8–10.5 g) were fed on TMLM diets three times a day until apparent satiation. Nile tilapia fed on TMLM levels were found to significantly (p < 0.05) boosted their growth and feed efficiency indices by up to 45%, after which their performance declined. In comparison to other treatments, larger villi length/width and increased digestive enzymes activity were observed at this level (TMLM45). At TMLM45, there were no signs of inflammation in the liver tissues but feeding the fish on TMLM60 and TMLM75 showed more vacuolated hepatocytes and fewer hepatic sinusoids. Total protein, albumin, and globulin contents showed significant (p < 0.05) increases in response to TMLM levels in fish feeds; meanwhile no significant (p > 0.05) changes in blood glucose were observed compared to the control one (TMLM0). The values of alanine and aspartate aminotransferase, total cholesterol, and triglycerides decreased significantly (p < 0.05) as TMLM levels increased in fish feeds. In addition, significant (p < 0.05) increases in antioxidant and immunological variables were observed in fish fed with TMLM diets, in particular TMLM45. The current study concluded that the substitution of FM protein by 45% TMLM protein in diets administered to Nile tilapia juveniles significantly improved (p < 0.05) their growth, antioxidant, and immune response compared to the control diet (FM-based diet). Full article

Sustainable phosphorus (P) management in agriculture requires a circular economy approach through the use of so-called bio-based fertilizers (BBFs). The properties of BBFs vary widely depending on raw materials and production processes. However, it is still unknown how these properties, and particularly the dominant P compounds determine not only the efficiency of BBFs in supplying P to crops, but also their effects on soil functioning and crop quality. This study aimed to evaluate the efficiency of a representative set of BBFs, and relate this efficiency to their composition and dominant P compounds. To this end, 14 BBFs were studied: four from water purification (struvite, vivianite, and sewage sludge with and without composting), four composts (municipal solid waste (MSW), vineyard residues, and two using olive husks), three vermicomposts (two homemade and one commercial), fish meal, digestate, and a commercial organic fertilizer. Phosphorus forms in BBFs were determined using ³¹P nuclear magnetic resonance spectroscopy (P-NMR). The BBFs were compared to a single superphosphate (SSP) in a pot experiment growing wheat in two different alkaline soils, one rich in iron (Fe) oxides and one rich in carbonates. The effects on critical elements in grain [magnesium, Fe, zinc (Zn), manganese, and copper] and enzyme activities related to soil functioning and P cycling were also assessed. The dominant P compound in the BBFs was orthophosphate (73.8–89.5% of the total P in the NaOH–EDTA extracts). The MSW had the highest polyphosphate content (4.1%), a complex inorganic P compound. The organic P content ranged from 9.2% (fish meal) to 25.5% (Moge). Sewage sludge and composted sludge contributed high levels of phosphonates (4.1 and 5.6% of extracted P). The most abundant organic P compound class was inositol hexakisphosphates (IHPs), and myo-IHP (phytate) was the dominant IHP stereoisomer (1.2–6.4%) followed by D-chiro-IHP and scyllo-IHP. Plant dry matter and grain yield with most BBFs were not significantly different from that of SSP in both soils, likely due to the high concentrations of phosphate in relatively soluble forms in most of the BBFs. Vivianite and sewage sludge resulted in significantly higher grain yield than SSP (43% and 40%, respectively) in the carbonate-rich soil, likely due to progressive phosphate dissolution, which decreased the precipitation rate of insoluble calcium (Ca) phosphates. The highest P recoveries were obtained with horse manure vermicompost (65% and 15% higher than SSP in the Fe oxide-rich and in the carbonate-rich soil, respectively), partially attributed to the decreased precipitation rate of insoluble Ca phosphates with the added organic matter. Some BBFs increased micronutrient concentrations in grains and most decreased the P-to-Zn ratio relative to SSP. Overall, phosphatase and β-glucosidase activities increased with carbon-rich BBFs. Most of the studied BBFs could effectively replace fertilizers from non-renewable sources, in some cases with better crop P recoveries. Furthermore, some BBFs could provide additional benefits to grain quality, in terms of micronutrient supply for humans, and soil functioning. Full article

A 7-week study was conducted to investigate the effects of replacing fish meal (FM) with Spirulina residue meal (SPRM) on the growth, feed utilization, carcass composition, antioxidant ability, liver and intestinal histology of juvenile rainbow trout (Oncorhynchus mykiss) (initial body weight 5.36 ± 0.04 g). Four isonitrogenous (42%) and isolipidic (16%) diets were formulated to replace FM protein with SPRM at 0 (SPRM0), 10% (SPRM10), 20% (SPRM20) and 30% (SPRM30), respectively. Results showed that growth, feed utilization, carcass amino acid profile, serum biochemical indices, antioxidant ability, intestinal and liver histology were not significantly affected by dietary SPRM levels. Whole-body lipid content decreased as dietary SPRM replacement levels increased, and fish fed diet SPRM30 had lower lipid content than that fish fed diet SPRM0 (p < 0.05). Fish fed diet SPRM30 had higher C16:1n-7, C20:3n-6, total saturated fatty acid (SFA) and total fatty acid (TFA) contents in muscle than those fed other diets (p < 0.05), while these fatty acids had no change when FM was substituted with 10% and 20% SPRM (p > 0.05). The muscle C22:6n-3 (DHA) content decreased, but C18:3n-6 and n-6/n-3 polyunsaturated fatty acid (PUFA) ratio increased with increasing SPRM levels, and fish fed diet SPRM30 had significantly lower DHA content and higher n-6/n-3 ratio than the group fed SPRM0 (p < 0.05). The C22:1n-9, C18:2n-6c, C20:4n-6, total n-6 PUFA, and monounsaturated fatty acid (MUFA) content in muscle observed in SPRM30 were similar to the SPRM0 group (p > 0.05), but higher than the SPRM10 and SPRM20 groups (p < 0.05). In conclusion, 30% of FM protein could be replaced by SPRM in diets of juvenile rainbow trout without having a significant negative effect on growth, feed efficiency, antioxidant ability, and structure of liver and intestine, but could reduce DHA content, increase n-6 PUFA and n-6/n-3 PUFA ratio in muscle. Full article

Background/Objectives: In gilthead seabream, the transition from fish meal/oil-based diets to diets with partial plant-based replacement is gaining ground due to price fluctuations and environmental concerns. Most studies focus on the dietary effects on important commercial traits such as body weight and fat deposition, while metabolic traits and their underlying genetic and transcriptional regulation remain largely unexplored. Methods: In the present study, the response of metabolic traits (protein, cholesterol, and triglycerides levels) was measured in gilthead seabream of different genetic backgrounds at 15 (D15) and 30 days (D30) after a shift from a fish meal/oil-based diet (FM) to a plant-based (PP) diet. Results: Moderate heritability of total protein and triglyceride content of blood was estimated on D30. Significantly positive genetic correlations were observed between triglyceride D30 content and final weight and muscle fat. No significant genotype-by-diet interaction effects were detected. At the end of the production cycle, final body weight and fat were recorded, and hepatic expressions of ghri, ghrii, igf1 and ttr genes were measured in a subpopulation of 160 fish. An overall negative correlation was recorded between the hepatic expression of igf1 and final weight, whereas strong positive correlations were observed between the expression of all hepatic genes measured. In the same population, fourteen SNPs located in the 3′ UTR of ghrii and igf1 genes were genotyped and analyzed in two ways, as a sum-of-risk score and individually as predictors for body weight, muscle fat, metabolic traits and hepatic expression levels. The sum-of-risk score was significantly associated with muscle fat and ttr expression. Studying the effect of each SNP independently, two SNPs in the igf1 gene were associated with ghrii expression levels and one SNP in igf1 gene was associated with triglyceride levels at day 15 (Trigl_D15) while one SNP in ghrii was associated with ttr expression levels. Focusing on the diet, it was significantly associated with final weight, muscle fat, protein (D30) and triglycerides levels, and hepatic expression levels of ghrii. Full article

The search for sustainable alternatives to fishmeal (FM) in aquafeeds represents a major challenge for modern aquaculture. This study evaluated the effects of replacing 35% of FM with defatted Hermetia illucens larvae meal (HIM35) in diets of gilthead seabream (Sparus aurata) reared under full-scale commercial offshore farming conditions. Fillet nutritional quality, fatty acid and amino acid profiles, mineral composition, and microbiological stability during refrigerated storage were assessed. Dietary HIM35 significantly modified the fatty acid profile, increasing saturated fatty acids, particularly lauric and myristic acids, and n-6 polyunsaturated fatty acids. Despite reductions in eicosapentaenoic and docosahexaenoic acids (EPA and DHA), total PUFA and lipid health indices remained within recommended ranges and EPA + DHA levels were above 8%, supporting both fillet nutritional value and fish physiological requirements. Enzymatic indices based on product-to-precursor fatty acid ratios suggested reduced Δ5 + Δ6-desaturase activity. The amino acid profile showed increases in selected essential and non-essential amino acids, while overall protein quality was preserved. HIM35 fillets showed lower sodium and higher zinc contents, whereas increased aluminum levels warrant further investigation. Microbiological analyses confirmed the absence of foodborne pathogens and no effects on spoilage dynamics. Overall, HIM35 represents a safe and effective partial replacement for FM supporting sustainable aquafeed strategies. Full article

A 6-week feeding trial evaluated composite protein mixtures as partial replacements for fish meal (FM) in diets for juvenile yellowtail (Seriola quinqueradiata). Five diets were prepared: a control diet (C) with FM as the main protein source, and four test diets in which 25% and 35% of FM protein were replaced by either a composite mixture of SSM (44% shark by-product meal + 56% surimi by-product mixture; SS25 and SS35) or SMM (58% shark by-product meal + 42% other by-product mixture; SM25 and SM35). Fish (initial mean weight 0.85 g) were stocked at 30 fish per 500-L tank, with three replicate tanks per treatment. Growth performance indicators, including final mean weight, percent weight gain, specific growth rate, daily feeding rate, and survival, did not differ significantly among treatments (p > 0.05). Feed efficiency was significantly higher in SS25 and SS35 than in the control (p < 0.05), whereas no significant differences were observed among the by-product-based diets. Whole-body proximate composition was unaffected, except for crude ash. The levels of key n-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, were significantly lower in SM25 and SM35 than in the control (p < 0.05). These results indicate that up to 35% of FM protein can be replaced with shark by-product-based mixtures without compromising growth in juvenile yellowtail. Full article

Subadult flathead grey mullets (Mugil cephalus) were fed three experimental diets containing increasing percentages of partially defatted black soldier fly (Hermetia illucens, BSF) that proportionally replaced the protein sources in the reference diet. At the end of the feeding trial, fish growth and gut, liver and spleen histology were evaluated. BSF inclusion did not significantly affect growth performances in any dietary groups. However, Fulton’s condition factor was lower in fish who were fed diets with the highest replacement levels (15% and 20%; BSF15 and BSF20) compared to those fed the 10% replacement (BSF10) and the control diet (BSF0). Histological analyses revealed increased villi thickness and mucous cell proliferation in the intestine of fish from BSF10 and BSF15 groups. A significant worsening of intestinal condition was observed in fish from the BSF20 group. Liver histology was not affected, while a dose-dependent effect on spleen was observed in fish fed BSF inclusions. Despite the absence of enteritis signs, an increase in macrophages/like TNF-α+ cells in the intestine mucosa indicated immune stimulation in the BSF10 group. Results indicate, for the first time, a threshold for BSF meal inclusion in diets specifically formulated for flathead grey mullets. The BSF10 diet was optimal, as growth performance was not affected and intestine health improved at both morphological and innate immune system levels. Full article

This study evaluated the effects of replacing fish meal (FM) with corn peptide (CP) in juvenile tiger puffer in indoor tanks. Four diets were formulated for a 53-day feeding trial: a control group (CP0), and diets with 5% (CP5), 10% (CP10), and 15% (CP15) CP replacing FM. Each diet was fed to triplicate tanks. No significant difference in weight gain was observed between CP5 and control (p > 0.05). However, when the CP inclusion level exceeded 10%, growth performance began to decline, with the CP15 group being significantly lower than the control. The feed intake was linearly increased by CP. The proximate body composition revealed no significant difference among treatments. The CP10 group showed significantly higher serum malondialdehyde content than the control. Significantly lower muscle fiber density was observed in CP10 and CP15 compared to the control. The taurine content was significantly reduced in CP10, while no significant differences were found for other amino acids. Compared with the control group, the CP5 group showed significantly elevated levels of free proline and glutamic acid. The intestinal expression of the peptide transporter gene pept1 was significantly up-regulated by CP. In conclusion, the appropriate inclusion level of corn peptide was 5% for juvenile tiger puffer. Full article

The aquafeed industry is currently facing severe challenges such as increasingly tight supply and price fluctuations of traditional high-quality protein ingredients like fish meal and soybean meal. Therefore, actively exploring and developing new, stable, efficient, and sustainable feed protein sources to replace fish meal and soybean meal has become an urgent task and an important strategic direction for ensuring the sustainable development of the aquaculture industry. Copra meal is a widely available plant protein source with lower cost compared to fish meal and soybean meal, demonstrating good application potential. However, copra meal has disadvantages including low protein content, imbalanced amino acid profile, high crude fiber content, numerous anti-nutritional factors, and low digestibility. These issues can be addressed through certain treatments (e.g., fermentation or water soaking) to enhance its nutritional value. Currently, research on copra meal in aquafeed is still relatively scarce. To enable the broader and more effective application of this promising feed ingredient in aquafeed, this review systematically summarizes the current research progress on the nutritional characteristics, appropriate inclusion levels, processing improvement technologies, and the effects of copra meal on the growth and health of aquatic animals, aiming to provide references for promoting resource diversification and sustainable development in the aquafeed industry. Full article

Quinoa germ meal (QGM) is a protein-rich by-product with potential as an alternative protein source; however, its effects on growth performance and intestinal health in marine carnivorous fish remain unclear. Juvenile turbot (Scophthalmus maximus) were fed five isonitrogenous (45.6% crude protein) and isolipidic (9.8% crude lipid) diets for 8 weeks: a fishmeal-based control diet (C) and four experimental diets in which fishmeal was replaced with QGM at 10% (Q10), 20% (Q20), 30% (Q30), and 40% (Q40). Growth performance, muscle proximate composition, intestinal histomorphology, and intestinal transcriptomic profiles were analyzed. Growth performance parameters, including final body weight, weight gain rate, specific growth rate, daily feed intake, and condition factor, decreased significantly with increasing QGM inclusion levels compared with the control (p < 0.05). Feed conversion ratio increased significantly only when replacement exceeded 30% (p < 0.05), while survival rate was unaffected (p > 0.05). Muscle crude lipid content was significantly reduced in all QGM-fed groups (p < 0.05), whereas crude protein, moisture, and ash contents were unchanged. Intestinal mucosal fold height increased in the Q30 and Q40 groups, while submucosal width decreased in the Q40 group (p < 0.05). Transcriptomic analysis revealed a dose-dependent increase in differentially expressed genes, mainly enriched in ribosome-related pathways, linoleic acid metabolism, and protein digestion and absorption. High dietary inclusion of QGM (>30%) impaired growth performance in juvenile turbot, whereas low inclusion levels (≤20%) exerted minimal adverse effects. Quinoa germ meal represents a potential alternative protein source, yet its effective utilization requires further optimization to maintain growth performance. Full article

Incorporating protein feed ingredients that exhibit strong attractiveness to the target fish species is an effective and sustainable feeding strategy to improve feed intake and enhance growth performance. An 8-week feeding experiment was performed to elucidate the manipulation impact of graded levels of jack mackerel meal (JMM) in diets replacing 10% fish meal (FM) with corn protein concentrate (CPC) on the growth, feed utilization, and blood chemistry of rockfish (Sebastes schlegeli), as well as to perform an economic analysis. A total of 450 fish were randomly assigned to 15 plastic tanks (30 juveniles/tank). Five experimental diets were formulated to be isoproteic (50.0% crude protein) and isolipidic (15.5% crude lipid). The control (Con) diet contained 55% FM. In the Con diet, 10% of the FM was substituted with CPC, and graded levels of JMM at 0%, 20%, 40%, and 60% were subsequently incorporated instead of the FM, referred to as CPCJ0, CPCJ20, CPCJ40, and CPCJ60, respectively. Triplicate groups of rockfish were carefully hand-fed the diets to satiation throughout the feeding experiment. The rockfish fed the CPCJ60 diet produced significantly higher weight gain (WG) (p < 0.002) and specific growth rate (SGR) (p < 0.003) than those fed the Con, CPCJ0, and CPCJ20 diets but showed no significant (p > 0.05) differences compared to those fed the CPCJ40 diet. Both the WG (Y = 0.9367X + 17.0500, p < 0.0001, Adjusted R² = 0.8468) and SGR (Y = 0.0005X + 0.0165, p < 0.0001, Adjusted R² = 0.8580) of the rockfish increased linearly with increased dietary JMM inclusion levels when 10% of the FM was replaced by CPC. The rockfish fed the CPCJ60 diet showed a significantly higher feed consumption (FC) (p < 0.03) compared to those fed the CPCJ0 diet. Among the dietary treatments, however, no significant (p > 0.05) differences were found in the feed utilization, proximate composition, amino and fatty acid profiles, and blood chemistry of the rockfish. The CPCJ60 diet resulted in the highest economic profit index (EPI) among the dietary treatments. Conclusively, JMM was found to be effective in improving the FC of rockfish fed the diets replacing 10% of the FM with CPC. Furthermore, the WG and SGR of the rockfish fed the diets replacing 10% of the FM with CPC improved linearly with elevated JMM inclusion. Thus, incorporating 60% of JMM into the diets substituting 10% of the FM with CPC was the most recommended strategy according to the growth performance and FC of the rockfish, providing the highest EPI for fish farmers. Full article

Poultry production faces considerable challenges in terms of feed costs and sustainability, particularly regarding conventional protein sources such as fish meal (FM). Insect-based proteins, such as housefly larvae (HL) meal, offer sustainable alternatives. Therefore, this study aimed to investigate the effects of HL on growth, gut health, metabolizable energy, and gut microbiota of broilers to clarify the availability of HL meal for broiler diet. Experiment 1 was performed to investigate the effects of replacing FM with HL on growth performance, intestinal morphology, cecal short-chain fatty acids, and gut microbiota composition and diversity in male broilers. Experiment 2 was performed to assess the digestibility of broiler diets containing HL. HL addition effectively maintained growth and improved intestinal morphology. Blood analysis revealed that HL addition reduced TNF-α levels and improved protein utilization. Additionally, HL substitution induced significant changes in the gut microbiota community and metabolic pathways. In conclusion, HL are a viable alternative to FM with adequate energy content and beneficial effects on gut health, supporting their use as a sustainable protein source. Full article

The global demand for fish oil (FO) is increasing while its supply is decreasing, which has limited its use in aquafeeds. Research on alternative terrestrial oils (TOs) for commonly cultured fish species in Bangladesh is limited. This research involved a 70-day feeding experiment to assess the effectiveness of replacing FO with TOs in the diet of Gangetic catfish (Mystus cavasius). Five diets were formulated: a control diet (D1) with fish meal and FO, and four diets replacing FO with soybean oil (D2), black soldier fly larvae oil (D3), palm oil (D4), or a mixed oil combination (D5) of 50% black soldier fly larvae oil, 25% soybean oil, and 25% palm oil. A total of 675 fish (0.5 g each) were distributed in 15 100 L aquariums (45 fish/aquarium) and fed to satiation twice daily. Fish fed with Diet D5 showed significantly higher growth, followed by those fed with D3, D4, and D1, while D2 resulted in significantly lower growth. Fish on the D5 diet consumed the most feed, followed by those on the D3 and D2 diets, with similar feed intake levels for those on the D1 and D4 diets. FCR, FCE, and PER were not significantly affected by dietary oil sources. Whole-body lipid content (p < 0.05) was significantly lower in the D3 group and higher in the D2 group, while other groups showed intermediate values. The fatty acid composition in the fish reflected their diets: significantly higher n-3 LC-PUFA (EPA + DHA) content was observed in the D1 group, followed by the D4 and D3 groups, and fish fed with D2 and D5 showed significantly lower values. Alpha-linolenic acid C18:3n-3) was significantly higher in the D2 group, followed by the D3, D1, and D4 groups, with the D5 group having a significantly lower value. Total MUFA was significantly higher in D4, followed by D1, D5, and D3; the D2-fed group showed a significantly lower value. Lauric acid (C12:0) was significantly higher in D3, followed by D5; other groups showed significantly lower values. Feed physical properties were significantly influenced by oil type, with water stability, pellet durability, and palatability being significantly highest in the D2 and D5 diets, followed by D3 and D4, with D1 being the lowest. Fish on the D1 and D5 diets had a significantly higher condition factor (CF) compared to fish on the D2 diet. Considering the growth and overall performance in the current study, we concluded that under the current dietary composition, TOs can effectively replace FO in the diets of Gangetic catfish, with mixed oils, black soldier fly larvae oil, and palm oil being the most promising alternatives. Full article